This invention relates to an indicator instrument for displaying the operating efficiency of a motor vehicle and more particularly it concerns an indicator instrument for a motor vehicle having an automatic transmission.
This application is related to my copending U.S. application Ser. No. 18,716, filed Mar. 8, 1979, now U.S. Pat. No. 4,223,553 in which an efficiency meter for an internal combustion engine equipped with a manually operated transmission is described. An essential aspect of the prior device is the generation of an indication only when the highest gear is engaged. Moreover, the arrangement described in the earlier patent application provides for an indicator instrument with opaque portions for the indicator positions corresponding to idling, engine-braking, and full load acceleration. Thus, the driver receives an efficiency indication only in a limited range of vehicle operation, namely, at cruising speed, which is the operating range occurring most frequently. When in the cruising range, it is important that the driver be provided with easily viewable information on engine efficiency, which will not detract his attention from the highway.